Iran's Islamic Revolutionary Guards Corps (IRGC) has warned "terrorists" that any future attacks against Iran could result in more retaliatory actions.

Iranian state-controlled television quoted IRGC spokesman Ramazan Sharif as making the comments on June 19, after Iran's elite force said it had fired missiles targeting the extremist group Islamic State (IS) in Syria following deadly attacks in Tehran earlier this month.

"If [IS militants] carry out a specific action to violate our security, definitely there will be more launches, with intensified strength," Sharif said.

The IRGC said on June 18 that it had launched several missiles from Iran into eastern Syria targeting IS fighters in retaliation for attacks on Iran's parliament and the shrine of the founder of the Islamic republic, Ayatollah Ruhollah Khomeini, that left 18 dead.

The twin attacks were claimed by the IS group. Iranian leaders have accused Saudi Arabia of involvement in the twin attacks, which Riyadh denies.

Sharif described the missile strikes as "successful" and warned the IS group and its "regional backers" against launching attacks on Iran.

"Obviously and clearly, some reactionary countries of the region, especially Saudi Arabia, have announced that they are trying to bring insecurity into Iran," he said.

Iran has been a key backer of Syrian President Bashar al-Assad during the country's civil war and the IRGC has played a crucial role on the ground.